Recombination and clonal groupings within Helicobacter pylori from different geographical regions

Mark Achtman, Takeshi Azuma, Douglas E. Berg, Yoshiyuki Ito, Giovanna Morelli, Zhi Jun Pan, Sebastian Suerbaum, Stuart A. Thompson, Arle Van Der Ende, Leen Jan Van Doorn

Research output: Contribution to journalArticlepeer-review

317 Scopus citations


A collection of 20 strains of Helicobacter pylori from several regions of the world was studied to better understand the population genetic structure and diversity of this species. Sequences of fragments from seven housekeeping genes (atpA, efp, mutY, ppa, trpC, urel, yphC) and two virulence-associated genes (cagA, vacA) showed high levels of synonymous sequence variation (mean percentage K(s) of 10-27%) and lower levels of non-synonymous variation (mean percentage K(a) of 0.2-5.6%). Cluster analysis of pairwise differences between alleles revealed the existence of two weakly clonal groupings, which included half of the strains investigated. All six strains isolated from Japanese and coastal Chinese were assigned to the 'Asian' clonal grouping, probably reflecting descent from a distinct common ancestor. The clonal groupings were not totally uniform; recombination, as measured by the homoplasy test and compatibility matrices, was extremely common within all genes tested, except cagA. The fact that clonal descent could still be discerned despite such frequent recombination possibly reflects founder effects and geographical separation and/or selection for particular alleles of these genes.

Original languageEnglish (US)
Pages (from-to)459-470
Number of pages12
JournalMolecular Microbiology
Issue number3
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


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